In the oil & gas sector, the creation of temporary or permanent underwater facilities for extracting and/or producing hydrocarbons from wells made in the bed of a body of water is generally known. In the context of the present description, the term “permanent” shall be understood to mean underwater facilities destined for working on the bed of the body of water for an unspecified number of years. In the following description, “hydrocarbon production” shall be understood to mean the extraction of hydrocarbons, the treatment of hydrocarbons, the treatment of fluids related to the production of hydrocarbons and/or the subsequent transport.
Underwater hydrocarbon production facilities can be located level with or close to underwater wells or in intermediate places, and they can take on various configurations on a bed of a body of water depending on the configuration of the well or the well field. Moreover, underwater hydrocarbon production facilities can be situated in shallow water or deep water and in all geographical areas regardless of whether the environmental conditions are relatively easy or relatively extreme.
The concept of an underwater hydrocarbon production facility was developed by various operators in the field with the aim of rationalizing the production of hydrocarbons from underwater wells. In short, an underwater hydrocarbon production facility is part of a relatively complex facility that comprises an underwater hydrocarbon production facility and pipes for relatively long distance transport between the underwater facilities and surface structures. The exploitation of underwater oil and/or gas or multiphase deposits by underwater hydrocarbon production facilities, which foresee the extraction and transport of the hydrocarbon to the surface or to the coast has been underway for some time and is expected to grow in the near future with increasingly complex facilities aimed at optimizing costs. Recent technological developments in underwater devices suitable for operating at a relatively great depth and the relatively great interest of oil companies have facilitated the feasibility of relatively complex systems, extended the potential of underwater production facilities and made it possible to produce facilities also containing active process elements in water, such as arranged on the bed of the body of water. The main underwater treatment processes are: single phase or multiphase pumping, compression and pumping of the gaseous fluid; two-phase and three-phase separation (for example liquid/liquid, gas/liquid, solid/liquid, oil/water/gas; deposit or sea water or hydrocarbon treatment and pumping and injection of water or gas in the well and injection of chemical products.
Further information on the current state of underwater hydrocarbon production and process facilities is available in the document OTC 24307 “STEPS TO THE SUBSEA FACTORY” by Rune Ramberg (Statoil), Simon R H Davies (Statoil), Hege Rognoe (Statoil), Ole Oekland (Statoil).
Underwater hydrocarbon production facilities undoubtedly often provide numerous advantages compared to surface ones, however, their construction, maintenance and control involve connecting and possibly fluidically disconnecting the function modules from the interconnecting unit inside the body of water to be able to maintain and/or repair them on the surface.
Connecting systems for conduits in a body of water can comprise both “permanent devices” such as devices which make it possible to keep the two conduits connected and make the seal, and “temporary devices” such as Remote Operated Vehicle (“ROV”) auxiliary devices which allow the operations needed for the connection to be carried out during the installation and/or maintenance phase. Generally, the connecting systems must principally perform two functions: recover the distance that separates the free ends of the two conduits; and seal the two conduits.
EP Patent No. 0733843, U.S. Pat. Nos. 4,648,626, 4,720,124, 4,561,662, 7,565,913 describe the technical solutions for carrying out at least one of the two functions. However, the above documents are not able to create a connecting system that is relatively compact, reversible and simple to use.